net: extract nf_ct_skb_network_trim function to nf_conntrack_ovs

There are almost the same code in ovs_skb_network_trim() and
tcf_ct_skb_network_trim(), this patch extracts them into a function
nf_ct_skb_network_trim() and moves the function to nf_conntrack_ovs.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Aaron Conole <aconole@redhat.com>
Acked-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

include/net/netfilter/nf_conntrack.h

@@ -362,6 +362,8 @@ static inline struct nf_conntrack_net *nf_ct_pernet(const struct net *net)
 	return net_generic(net, nf_conntrack_net_id);
 }
 
+int nf_ct_skb_network_trim(struct sk_buff *skb, int family);
+
 #define NF_CT_STAT_INC(net, count)	  __this_cpu_inc((net)->ct.stat->count)
 #define NF_CT_STAT_INC_ATOMIC(net, count) this_cpu_inc((net)->ct.stat->count)
 #define NF_CT_STAT_ADD_ATOMIC(net, count, v) this_cpu_add((net)->ct.stat->count, (v))

net/netfilter/nf_conntrack_ovs.c

@@ -102,3 +102,29 @@ int nf_ct_add_helper(struct nf_conn *ct, const char *name, u8 family,
 	return ret;
 }
 EXPORT_SYMBOL_GPL(nf_ct_add_helper);
+
+/* Trim the skb to the length specified by the IP/IPv6 header,
+ * removing any trailing lower-layer padding. This prepares the skb
+ * for higher-layer processing that assumes skb->len excludes padding
+ * (such as nf_ip_checksum). The caller needs to pull the skb to the
+ * network header, and ensure ip_hdr/ipv6_hdr points to valid data.
+ */
+int nf_ct_skb_network_trim(struct sk_buff *skb, int family)
+{
+	unsigned int len;
+
+	switch (family) {
+	case NFPROTO_IPV4:
+		len = skb_ip_totlen(skb);
+		break;
+	case NFPROTO_IPV6:
+		len = sizeof(struct ipv6hdr)
+			+ ntohs(ipv6_hdr(skb)->payload_len);
+		break;
+	default:
+		len = skb->len;
+	}
+
+	return pskb_trim_rcsum(skb, len);
+}
+EXPORT_SYMBOL_GPL(nf_ct_skb_network_trim);

net/openvswitch/conntrack.c

@@ -1091,36 +1091,6 @@ static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
 	return 0;
 }
 
-/* Trim the skb to the length specified by the IP/IPv6 header,
- * removing any trailing lower-layer padding. This prepares the skb
- * for higher-layer processing that assumes skb->len excludes padding
- * (such as nf_ip_checksum). The caller needs to pull the skb to the
- * network header, and ensure ip_hdr/ipv6_hdr points to valid data.
- */
-static int ovs_skb_network_trim(struct sk_buff *skb)
-{
-	unsigned int len;
-	int err;
-
-	switch (skb->protocol) {
-	case htons(ETH_P_IP):
-		len = skb_ip_totlen(skb);
-		break;
-	case htons(ETH_P_IPV6):
-		len = sizeof(struct ipv6hdr)
-			+ ntohs(ipv6_hdr(skb)->payload_len);
-		break;
-	default:
-		len = skb->len;
-	}
-
-	err = pskb_trim_rcsum(skb, len);
-	if (err)
-		kfree_skb(skb);
-
-	return err;
-}
-
 /* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
  * value if 'skb' is freed.
  */
@@ -1135,9 +1105,11 @@ int ovs_ct_execute(struct net *net, struct sk_buff *skb,
 	nh_ofs = skb_network_offset(skb);
 	skb_pull_rcsum(skb, nh_ofs);
 
-	err = ovs_skb_network_trim(skb);
-	if (err)
+	err = nf_ct_skb_network_trim(skb, info->family);
+	if (err) {
+		kfree_skb(skb);
 		return err;
+	}
 
 	if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
 		err = handle_fragments(net, key, info->zone.id, skb);

net/sched/act_ct.c

@@ -726,31 +726,6 @@ static bool tcf_ct_skb_nfct_cached(struct net *net, struct sk_buff *skb,
 	return false;
 }
 
-/* Trim the skb to the length specified by the IP/IPv6 header,
- * removing any trailing lower-layer padding. This prepares the skb
- * for higher-layer processing that assumes skb->len excludes padding
- * (such as nf_ip_checksum). The caller needs to pull the skb to the
- * network header, and ensure ip_hdr/ipv6_hdr points to valid data.
- */
-static int tcf_ct_skb_network_trim(struct sk_buff *skb, int family)
-{
-	unsigned int len;
-
-	switch (family) {
-	case NFPROTO_IPV4:
-		len = skb_ip_totlen(skb);
-		break;
-	case NFPROTO_IPV6:
-		len = sizeof(struct ipv6hdr)
-			+ ntohs(ipv6_hdr(skb)->payload_len);
-		break;
-	default:
-		len = skb->len;
-	}
-
-	return pskb_trim_rcsum(skb, len);
-}
-
 static u8 tcf_ct_skb_nf_family(struct sk_buff *skb)
 {
 	u8 family = NFPROTO_UNSPEC;
@@ -1011,7 +986,7 @@ TC_INDIRECT_SCOPE int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
 	if (err)
 		goto drop;
 
-	err = tcf_ct_skb_network_trim(skb, family);
+	err = nf_ct_skb_network_trim(skb, family);
 	if (err)
 		goto drop;